METHOD FOR RETURNING FORCE IN A MOTORIZED GUIDE DEVICE OF A VEHICLE WITH ASSISTED DRIVING

Abstract

Title: METHOD FOR FORCE FEEDBACK IN A GUIDE MECHANISM OF A VEHICLE WITH ASSISTED DRIVING The invention relates to a method for force feedback in a motorized guidance member of a vehicle with assisted driving comprising a computer, the method being implemented by the computer and comprising: - a first step (C1) in which a discretized reference trajectory is determined intended to be followed by the vehicle, as a function of instantaneous parameters of the vehicle measured by the motorized guidance member, - a second step (C2) during which the control member determines an optimal discretized trajectory of the vehicle as a function of the reference trajectory allowing the vehicle to follow said reference trajectory of the vehicle without encountering an obstacle,- a third step (C3) during which a force law to be provided by the driver for a movement of the guide member is calculated as a function of the reference trajectory and the optimal trajectory, so as to generate haptic feedback in the guide member, - a fourth step (C4) during which a control of the force to be provided by the driver for the movement of the motorized guide member is applied using the force law determined previously. Figure for the abstract: [Fig 1],

Description

Title of the invention: METHOD FOR RETURNING FORCE IN A MOTORIZED GUIDE MEANS OF A VEHICLE WITH ASSISTED DRIVING Technical field

[0001] The present invention relates to methods relating to assisted driving vehicles and more particularly to haptic technologies embedded in such vehicles.

[0002] Such vehicles with assisted driving or guidance are generally called “semi-autonomous”.

[0003] Driving assistance has the advantage of proposing a trajectory to be followed by said vehicle. Said trajectory can be calculated by calculation means on board said vehicle.

[0004] In other words, the assisted driving vehicle will follow a trajectory determined by a control algorithm defining all of the waypoints of said vehicle as well as the commands enabling such a route to be implemented.

[0005] For this purpose, the assisted driving vehicle calculates a future trajectory to follow based on the intention of its driver, called the “reference” trajectory, the intention being capable of being characterized by the force exerted on one or more pedals, in particular a gear pedal or via a steering (or guidance) member of the vehicle such as a car steering wheel or a joystick.

[0006] The reference trajectory does not take into account the obstacles likely to be encountered by the vehicle on this trajectory, nor the characteristics of the vehicle.

[0007] In the case of motor vehicles, a classification defined by the International Organization of Motor Vehicle Manufacturers classifies vehicles according to their level of assistance. This classification ranges from level zero in which the motor vehicle is said to be in manual driving, in other words without any assistance to the driver, to level five where the vehicle is completely autonomous and therefore without the possibility of intervention by its driver.

[0008] In this case, the invention then applies to any motor vehicle having a level of assistance intended to be between level two, called “partial assistance”, and level three, called “conditioned autonomy”.

[0009] More specifically, the “partial assistance” level requires the driver to monitor the road and control the trajectory in the event of a problem.

[0010] However, acceleration and deceleration are handled by the system and therefore the motor vehicle. In certain driving modes, a motorized guidance member such as the steering wheel is also handled by the system. The vehicle can include additional assistance such as adaptive cruise control.

[0011] The driver is then responsible for monitoring the vehicle's surroundings during the journey and for immediately regaining control in the event of a problem.

[0012] In level three, known as "conditioned autonomy", in which control of the vehicle in the event of a problem is carried out by its driver, the vehicle must monitor its driving environment and must act accordingly in complete autonomy under certain driving conditions.

[0013] Furthermore, the invention is applicable to so-called “Drive by Wire” vehicle systems in which the mechanical transmission parts for guiding and braking the vehicle have been replaced by actuators capable of being controlled, or to vehicle systems in which the mechanical transmission parts are present but disengaged. Previous techniques

[0014] It is known, in current “Drive by Wire” systems integrated into assisted driving vehicles, and more particularly in motor vehicles, to artificially simulate a mechanical steering column via a force feedback system coupled to the steering wheel of said motor vehicle so that the driver retains his cognitive references linked to the guidance of the vehicle.

[0015] For example, patent applications WO 2020 / 230307 A1 and WO 2014 / 073180 relate to the transition from “Drive by Wire” driving, simulating a mechanical steering column, to so-called conventional driving, i.e. using a clutch.

[0016] None of these documents teaches how to assist a driver in driving a motor vehicle using haptic force feedback in a motorized guidance member such as a steering wheel, said haptic force feedback being based on the difference between the reference trajectory desired by the driver and the optimal trajectory determined by an algorithm capable of being implemented by a computer on board the vehicle. Statement of the invention

[0017] The invention aims to overcome at least some of the aforementioned drawbacks and to propose a method capable of combining the advantages of speed, simplicity and reliability for its implementation.

[0018] In view of the above, the subject of the invention is a method of haptic force feedback in a motorized guidance member of a vehicle with assisted driving comprising a computer, the method being implemented by the computer and comprising:

[0019] - a first step in which a discretized trajectory of reference intended to be followed by the vehicle, based on instantaneous vehicle parameters measured by the motorized guidance device,

[0020] - a second step in which an optimal discretized trajectory is determined of the vehicle according to the reference trajectory allowing the vehicle to follow said reference trajectory of the vehicle without encountering an obstacle,

[0021] - a third step in which we calculate a law of force to be provided by the driver for the movement of the guide member according to the reference trajectory and the optimal trajectory so as to generate haptic feedback in the guide member,

[0022] - a fourth step during which a force control is applied to provided by the driver for the movement of the motorized guide member using the force law determined previously.

[0023] Preferably, the optimal trajectory and the reference trajectory are discrete trajectories.

[0024] For example, a parameter of deviation between the optimal trajectory and the reference trajectory is calculated from at least one point of the optimal trajectory and at least one point of the reference trajectory in order to calculate the force law during the third step.

[0025] Advantageously, the deviation parameter is a function of an area formed between two points of the optimal trajectory and a point of the reference trajectory, or between a point of the optimal trajectory and two points of the reference trajectory.

[0026] Preferably, the deviation parameter is a function of the area of ​​a first triangle and the area of ​​a second triangle, the first triangle being formed by a first point of the optimal trajectory, a second point of the optimal trajectory and a first point of the reference trajectory, and the second triangle being formed by said first point of the reference trajectory, a second point of the reference trajectory, and said second point of the optimal trajectory.

[0027] Preferably, the force law calculated during the third step is a function of the deviation parameter according to an even and positive function.

[0028] Advantageously, the force law calculated during the third step is a function of the deviation parameter according to a linear function.

[0029] Preferably, to use the force law as a function of the deviation parameter during the fourth step, a rotating reference frame is defined which is repositioned at each sampling period of the computer, said rotating reference frame being centered on a so-called optimal angular position of the motorized guidance member corresponding to a superposition of the reference trajectory and the optimal trajectory at several points of the optimal trajectory upstream of the vehicle in its direction of travel and to a minimum of the force to be provided by the driver for the movement of the guidance member. motorized, so that said force is minimal when the angle of said motorized guide member corresponds substantially to said superposition of said trajectories and, the force increasing as soon as the angle of the motorized guide member is moved away from the optimal angular position of said member.

[0030] Preferably, during the second step, the optimal trajectory is determined by taking into account constraints of the computer, the constraints of the control system being chosen individually or cumulatively from:

[0031] - an absence of obstacle upstream of the vehicle in its direction of travel on its track optimal jectory;

[0032] - an admissible speed interval;

[0033] - an admissible angular steering interval of the vehicle wheels;

[0034] - an admissible interval of acceleration or deceleration of the vehicle;

[0035] - an admissible interval of variation of the acceleration or deceleration;

[0036] - an admissible interval of variation of the steering angle of the wheels;

[0037] - geometric constraints of the vehicle;

[0038] - dynamic constraints of the vehicle;

[0039] - energy consumption constraints;

[0040] - instantaneous power constraints;

[0041] - a constraint of non-rolling of the vehicle.

[0042] The instantaneous parameters of the vehicle comprise, for example, a kinetic component and a directional component of the vehicle.

[0043] The invention also relates to a vehicle with assisted driving comprising:

[0044] - means for directional and kinetic guidance of the vehicle comprising a member motorized guidance with haptic feedback;

[0045] - a calculator configured to implement the method as defined above cededly. Brief description of the drawings

[0046] The invention will be better understood from a detailed study of an embodiment taken as a non-limiting example and illustrated by the appended drawings, in which:

[0047] [Fig. 1] represents a method of force feedback in a motorized guidance member of a vehicle with assisted driving having a calculator of a future trajectory of the vehicle.

[0048] [Fig.2] represents a reference trajectory, an optimal trajectory of the vehicle and a geometric method for calculating a deviation parameter between these two trajectories.

[0049] [Fig.3] represents a reference trajectory and an optimal trajectory of the vehicle in a first movement scenario.

[0050] [Fig.4] represents a force law applied to a motorized guide member of the vehicle depending on the angle of this organ, in the first scenario of [Fig.3].

[0051] [Fig.5] represents a reference trajectory and an optimal trajectory of a vehicle in a second movement scenario.

[0052] [Fig.6] represents a force law applied to the motorized guidance member of the vehicle as a function of its angle, in the second scenario of [Fig.5]. Detailed description

[0053] [Fig.l] illustrates the method of the invention implemented in a vehicle with assisted driving having a calculator of a future trajectory of the vehicle, which allows feedback to the driver of said vehicle as a function of the proximity of an optimal trajectory calculated by a member for predicting a future trajectory of the vehicle control system and the trajectory that the driver wishes to have the vehicle take.

[0054] The organ for predicting a future trajectory is, for example, a predictive control system.

[0055] Alternatively, it is possible to use another control method known to those skilled in the art, for example the so-called “LQ” control, chained forms or even reinforcement methods.

[0056] The method begins with a first step S1 during which the vehicle is started, then continues with steps S2 and S3 in which the vehicle detects whether the driver acts on the vehicle's driving control members.

[0057] The driving control members may comprise a steering wheel, a joystick, a lever and / or a pedal. At least one of these members generates a direction or speed instruction via the computer during step S2 and the computer records the instruction given by this member on the driving.

[0058] The driving control members comprise at least one motorized guidance member, for example a motorized steering wheel, which is systematically used during step S3, which makes it possible to give at least one steering instruction via the computer, and optionally to give at the same time the speed instruction via the computer.

[0059] The vehicle has, for example, a pedal delivering a speed instruction and a motorized steering wheel for driving the vehicle, allowing the driver to respectively provide a speed instruction via the computer and a vehicle orientation instruction during steps S2 and S3.

[0060] The vehicle comprises the motorized guidance member having a haptic feedback motor, as well as wheels. Preferably, the vehicle does not comprise any steering column between said motorized guidance member and said wheels.

[0061] Alternatively, the steering column is present, but disengaged.

[0062] The method is therefore applicable to so-called “Drive by Wire” vehicles in which the mechanical transmission parts for guidance and braking have been replaced by electrically controlled actuators.

[0063] The reference trajectory of the vehicle corresponds to the theoretical trajectory that the driver wishes the vehicle to take through the motorized guidance member and any other vehicle driving control members.

[0064] Steps S2 and S3 continue once both have been completed by a step C1 during which a discretized reference trajectory is determined intended to be followed by the vehicle as a function of instantaneous parameters of the vehicle measured by the motorized guidance member, said instantaneous parameters of the vehicle preferably comprising a kinetic component and a directional component of the vehicle, obtained for example by the instruction of steps S2 and S3.

[0065] Step C1 continues with a step C2 during which a vehicle control system determines an optimal discretized trajectory of the vehicle and the controls allowing it to be followed. The optimal trajectory is a function of the reference trajectory. This optimal trajectory allows the trajectory to be followed while respecting the various aforementioned constraints.

[0066] In a preferred mode, the determination of the optimal discretized trajectory of the vehicle can take into account characteristics of the vehicle.

[0067] The reference trajectory is therefore a trajectory used as the vehicle trajectory objective by the control system.

[0068] Alternatively, the reference and optimal trajectories are discrete trajectories rather than continuous trajectories.

[0069] The vehicle may further comprise sensors adapted to provide measurements to the control system for calculating the optimal trajectory and for controlling the actual trajectory of the vehicle to the optimal trajectory.

[0070] The control system therefore aims to make the vehicle follow the reference trajectory, taking into account constraints which generate a difference between the reference trajectory targeted by the vehicle and calculated during step C1, and the optimal trajectory actually taken by the vehicle and calculated during step C2.

[0071] The constraints of the control system are for example chosen individually or combined during step C2, to determine the optimal trajectory by taking into account constraints of the control member which provides the optimal trajectory, among: an absence of obstacle of the vehicle on the optimal trajectory, an admissible speed interval, an admissible angular steering interval of the wheels of the vehicle, an admissible acceleration or deceleration interval of the vehicle, an admissible variation interval of the acceleration or deceleration, an admissible variation interval of the steering angle of the wheels, geometric constraints of the vehicle, dynamic constraints of the vehicle, instantaneous power constraints, energy consumption constraints or even constraints of non-rolling of the vehicle.

[0072] These constraints of the control system allow it to generate an optimal trajectory which is free from danger for the vehicle and its occupants, which respects the mechanical constraints of the vehicle, and which increases the comfort felt.

[0073] Step C2 continues with a step C3 during which a force law to be provided by the driver for the movement of the motorized guide member in step S3 is calculated as a function of the reference trajectory and the optimal trajectory so as to generate haptic feedback in the guide member.

[0074] At the end of the third step C3, unless the driver opposes the movement / displacement of the guide member, the movement of said member in step S3 is done automatically by its integrated motor which angularly positions it on an angle Theta corresponding to the angle of the motorized guide member that the driver should choose for the orientation of the reference trajectory, i.e. identical to the orientation of the optimal trajectory.

[0075] In such a vehicle, the motorized guide member does not automatically cause the wheels to rotate and the vehicle to be guided.

[0076] On the contrary, whatever the movement and position of the motorized guidance member, the driver can set it in motion, for example in rotation, to indicate to the control system the angle that he wishes to see instilled in the trajectory of the vehicle, and thus allow said system to calculate the reference trajectory.

[0077] Step C3 continues with step S4 during which filtering is carried out, so as to filter out any jolts in the motorized guide member.

[0078] Filtering makes it possible to limit the influence of points too far from the current trend, i.e. to limit rapid variations in the force law.

[0079] Rapid variation means any sudden or uncomfortable movement of the vehicle for the driver.

[0080] The vehicle can still perform a quick dodge which will not be filtered, within the limits of these capacities defined by the aforementioned constraints.

[0081] The filtering compares the reference trajectory to the optimal trajectory or the force law to a threshold value, and in the event of too sudden a deviation for a preconfigured duration between the reference trajectory and the optimal trajectory or between the force law and a threshold value, then the vehicle is for example maintained in the optimal trajectory without taking into account the source value of sudden variation in the establishment of the reference trajectory, and step S4 then continues with an exit step S5, otherwise it continues with step C4.

[0082] Alternatively, steps C3 and S4 may be reversed, so that step S4 immediately precedes step C3.

[0083] During step S5, the current sampling period is ended, and a new process can be initiated from step S1 during a new sampling.

[0084] The force law to be provided by the driver for the movement of the motorized guide member is used during step C4, during which a control of the force to be provided by the driver for the movement of the motorized guide member is applied using the force law determined previously.

[0085] The force to be provided is for example regulated in the motorized guide member directly, by regulating the torque, friction, inertia and / or damping of the force provided...

[0086] This produces haptic feedback from the motorized guidance member to the driver's hands, allowing the driver to know in real time the difference between the reference trajectory and the optimal trajectory determined by the control member. This information reaches the driver through the difficulty in moving the guidance member as a function of the difference between the reference trajectory and the optimal trajectory.

[0087] In particular, if the driver has turned the motorized guidance member during step S3 into an angular position involving a difference between the reference trajectory created and the optimal trajectory, the method allows the driver to find a reference point by the guidance member to estimate the optimal trajectory that the vehicle will follow.

[0088] The force feedback therefore makes it possible to indicate to the driver to what extent the vehicle will follow the trajectory that he proposes.

[0089] Without this feedback, the driver is lost and the vehicle is difficult to drive.

[0090] [Fig.2] illustrates an example of a modeled vehicle 1 having a trajectory optimal L1 and a reference trajectory L2.

[0091] The calculator generates the optimal trajectory L1 following the direction of advance of the modeled vehicle 1 which is the same as that of the reference trajectory L2.

[0092] It is possible to have a similar operation when the vehicle is moving forward or backward, and the direction of travel of the vehicle is defined accordingly.

[0093] Preferably, the optimal trajectory and the reference trajectory are discrete.

[0094] A set of points forming said trajectories is thus obtained.

[0095] The set of points extends for example to twenty points which are spaced proportionally to the instantaneous speed of the vehicle.

[0096] The points are preferably spaced apart by a distance less than the distance traveled by the vehicle in one tenth of a second.

[0097] The method may further provide for the calculation of a parameter of deviation between the optimal trajectory and the reference trajectory from at least one point of the optimal trajectory PO1, PO2, PO3 and from at least one point of the reference trajectory PR1, PR2, PR3 for the calculation of the force law during the third step C3.

[0098] The calculation of a deviation parameter allows the control system to evaluate the deviation between the optimal trajectory and the reference trajectory, and to deduce therefrom a calibration of the movement force of the motorized guide member.

[0099] It is not necessary to take into account all of the trajectories for the calculation of the deviation parameter; a subdivision of these trajectories may be sufficient.

[0100] The deviation parameter may comprise the distance between two time-coherent points of the two trajectories (called reference and optimal), i.e. sampled simultaneously, or may comprise an angle between these two points, the angle being formed by the point of the optimal trajectory, the center of gravity of the vehicle and the point of the reference trajectory. The methods known as the “polynomial method”, “tangent method”, “trapezoid method” or even the “integral method” may be used to determine the deviation parameter between the two trajectories L1, L2.

[0101] In the polynomial method, the trajectories are modeled by polynomials, then the value of the integrals of these polynomials is used.

[0102] In the trapezoid method, the sum of the areas of all the trapezoids between the points of the reference trajectory and the optimal trajectory is calculated.

[0103] In the tangent method, the derivative is calculated at each point of the trajectory, said derivative calculation being for example carried out by any known method such as the finite difference method, then the average of the differences of the tangents at each point between the reference trajectory and the optimal trajectory is calculated.

[0104] Advantageously, the deviation parameter is a function of an area formed between two points of the optimal trajectory and a point of the reference trajectory and between a point of the optimal trajectory and two points of the reference trajectory.

[0105] This method using an area between the two curves of the trajectories L1, L2 as a deviation parameter is an effective compromise between calculation time and precision.

[0106] We thus use the method called the “triangle method”, which makes it possible to maximize the saving in calculation time, in which the deviation parameter is a function of both the area of ​​a first triangle and the area of ​​a second triangle, the first triangle being formed by a first point PO1 of the optimal trajectory L1, a second point PO2 of the optimal trajectory L1 and a first point PR1 of the reference trajectory L2, and the second triangle being formed by said first point PO1 of the reference trajectory L2, a second point PR2 of the reference trajectory L2, and said second point PO2 of the optimal trajectory LL

[0107] Figures 3 and 5 illustrate a first and a second scenario in which the gap between the optimal trajectory L1 and the reference trajectory L2 are respectively low and high.

[0108] Figures 4 and 6 respectively illustrate the forces to be provided in the guidance member by the driver in the form of torque in Newton-meters, as a function of the angle of said motorized guidance member in the first and in the second scenario.

[0109] Advantageously, the force law calculated during the third step C3 is a function of the deviation parameter according to a linear function.

[0110] Thus, the movement force to be provided by the driver for the movement of the motorized guide member is a function of the angle of said member, noted Theta in Figures 4 and 6, and also a function of the deviation parameter.

[0111] For example, the law between the movement force and the angle and that between the movement force and the gap are linear functions, for example proportionality functions.

[0112] As shown in these Figures 4 and 6, the greater the difference between the two trajectories L1, L2 of Figures 3 and 5, the greater the slope of the force curve.

[0113] Linearity allows better anticipation of haptic feedback by the driver, which gives him better predictability of the intention of the control system and therefore a better understanding of the optimal trajectory that will be taken by the vehicle.

[0114] If the slope of the force curve is directly equal to the average of the areas of a plurality of triangles calculated according to the triangle method equal to one, this is equivalent to a coefficient of proportionality equal to one.

[0115] An alternative is to sum the areas of these triangles and then use a slope proportional to the value obtained.

[0116] The force law calculated during the third step C3 is preferably a function of the position of the steering member according to an even and positive function, that is to say a function with positive values ​​symmetrical with respect to the ordinate axis.

[0117] Thus, the force law calculated during the third step C3 is a function which is even more predictable for the driver, because it gives the same control of the force to be provided by the driver for the movement of the motorized guide member regardless of the direction of movement of the motorized guide member, i.e. the distance from an ordinate axis corresponding to a given position of angle Theta equal to zero.

[0118] The method may further provide for defining a rotating reference frame repositioned at each sampling period of the calculator to obtain the parameters of the law as a function of the deviation during the fourth step C4, the deviation giving the parameters of the law (for example the slope in the case of a linear relationship) and the orientation of the motorized guide member giving the rotation of the rotating reference frame.

[0119] The rotating reference mark is centered on a so-called optimal angular position of the motorized guide member corresponding substantially to a superposition of the reference trajectory and the optimal trajectory at a point PO1, PO2, PO3 of the optimal trajectory and to a minimum of the effort to be provided by the driver for the movement of the motorized guide member.

[0120] Thus, the effort to be provided by the driver for the movement of said member is minimal when the angle Theta corresponds substantially to said superposition of said trajectories, and this effort increases as soon as the angle of the motorized guide member is moved away from the optimal angle of said member.

[0121] It may also be provided that the deviation parameter is subjected to the filtering of step S4, so as to filter out any jolts in the motorized guide member.

[0122] This filtering only applies to the movements of the motorized guidance member and is carried out at the same sampling period as the control law. Thus, in the event of an obstacle appearing on the optimal trajectory L1, implying that the vehicle quickly changes trajectory, the guidance member is prevented from turning too quickly in an uncomfortable manner for the driver by smoothing the values.

[0123] The invention also relates to a vehicle with assisted driving comprising:

[0124] - means for directional and kinetic guidance of the vehicle comprising a member motorized guidance with haptic feedback;

[0125] - a computer configured to implement the method as described above cededly.

[0126] A method is thus implemented which comprises, in parallel with conventional guidance assistance, the generation of haptic force feedback dependent on the rotating and precise reference point in the motorized guidance member intended for the driver to enable him to immediately perceive the difference between the reference trajectory indicated to the vehicle and the optimal trajectory resulting from the system control finally applied to the vehicle, the intensity of this force being linked to this difference so that the force feedback is understandable from a sensory point of view by the driver.

Claims

Claims

1. Method for force feedback in a motorized guidance member of a vehicle with assisted driving comprising a computer, the method being implemented by the computer and comprising: - a first step (Cl) in which a discretized reference trajectory intended to be followed by the vehicle is determined, as a function of instantaneous parameters of the vehicle measured by the motorized guidance member, - a second step (C2) in which an optimal discretized trajectory of the vehicle is determined as a function of the reference trajectory allowing the vehicle to follow said reference trajectory of the vehicle without encountering an obstacle,- a third step (C3) in which a deviation parameter between the optimal trajectory and the reference trajectory is calculated from at least one point of the optimal trajectory and at least one point of the reference trajectory in order to calculate a law of the force to be provided by the driver for a movement of the guidance member, as a function of the reference trajectory and the optimal trajectory, so as to generate haptic feedback in the guidance member, said deviation parameter being a function of an area formed between two points of the optimal trajectory and a point of the reference trajectory, or between a point of the optimal trajectory and two points of the reference trajectory, - a fourth step (C4) during which a control of the force to be provided by the driver for the movement of the motorized guidance member is applied, using the force law determined previously.,

2. The method of claim 1, wherein the optimal trajectory and the reference trajectory are discrete trajectories.

3. A method according to any one of claims 1 and 2, wherein the deviation parameter is a function of both the area of ​​a first triangle and the area of ​​a second triangle, the first triangle being formed by a first point of the optimal trajectory, a second point of the optimal trajectory and a first point of the reference trajectory, and the second triangle being formed by said first point of the reference trajectory, a second point of the reference trajectory, and said second point of the optimal trajectory.

4. Method according to any one of claims 1 to 3, in which the force law calculated during the third step (C3) is a function of the deviation parameter according to an even and positive function.

5. Method according to any one of claims 1 to 4, in which the force law calculated during the third step (C3) is a function of the deviation parameter according to a linear function.

6. Method according to claim 5, in which to use the coefficient of the force law as a function of the deviation parameter during the fourth step (C4), a rotating reference frame is defined which is repositioned at each sampling period of the calculator, said rotating reference frame being centered on a so-called optimal angular position of the motorized guidance member corresponding substantially to a superposition of the reference trajectory and the optimal trajectory at several points of the optimal trajectory upstream of the vehicle in its direction of advance and to a minimum of the force to be provided by the driver for the movement of the motorized guidance member, so that said force is minimal when the angle of said member corresponds substantially to said superposition of said trajectories, and the force increases as soon as the angle of the motorized guidance member is moved away from the optimal angular position of said member.

7. Method according to any one of claims 1 to 6, in which in which during the second step (C2), the optimal trajectory is determined by taking into account constraints of the computer, the constraints of the computer being chosen individually or cumulatively from: an absence of obstacle upstream of the vehicle in its direction of advance on its optimal trajectory, an admissible speed interval, an admissible angular steering interval of the wheels of the vehicle, an admissible acceleration or deceleration interval of the vehicle, an admissible interval of variation of the acceleration or deceleration, an admissible interval of variation of the steering angle of the wheels, geometric constraints of the vehicle, dynamic constraints of the vehicle, instantaneous power constraints, energy consumption constraints, or constraints of non-rolling of the vehicle.

8. Method according to any one of claims 1 to 7, in which during the fourth step (C4), the control of the force to be provided by the driver for the movement of the motorized guide member is also applied as a function of friction parameters and / or

9.

10. damping and / or inertia of the movement of said organ. A method according to any one of claims 1 to 8, wherein the instantaneous parameters of the vehicle comprise a kinetic component and a directional component of the vehicle. Assisted driving vehicle (1) comprising: - means of directional and kinetic guidance of the vehicle comprising a motorized guidance member with haptic feedback; - a computer configured to implement the method according to any one of claims 1 to 9.

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